Rectifier.



1. M. FITZGERALD.

RECTIFIER.

APPLICATiON FILED FEB. l5, 1915.

1,21 1,694. Patented Jan. 9, 1917.

4 SHEETS-SHEET l.

J. M. FITZGERALDI RECTIFIER.

APPUCTION FILED FEB.15,1915. 1,21 1,694, Patented Jan. 9, 1917.

4 SHEETS-SHEET 2.

Faye/21074 J. M. FITZGERALD.

RECTIFIER.

APPLICATION FILED FEB. I5, I9I5.

1,21 1,694. Patented Jan. 9,1917.

UNTTED STATES PATENT OFFICE.

JOHN M. FITZGERALD, 0F CHICAGO, ILLINOIS, ASSIGNOR TO HENRY S. HAWLEY, OF CHICAGO, ILLINOIS; THE MERCHANTS LOAN AND TRUST COMPANY, EXECUTOR OF SAID HENRY S. HAWLEY, DECEASED.

RECTIFIEB.

Specification of Letters Patent.

Application tiled February 15, 1915. Serial No. 8,178.

To all whom it may concern Be it known that l, JOHN M. FITZGERALD, a citizen of the United States, residing at Chicago` in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Rectiiers, of which the following is a specification.

My invention relates to rectifiers, and refers particularly to apparatus for convertin alternating current into uni-directional pu sating current, and vicevversa.

The general type of apparatus to which my invention relates is disclosed in Letters Patent Nos. 1,119,951, 1,120,615 and 1,120,616, issued in the name of Varian M. Harris on December 8, 1914.

It is one of the objects of my invention to rovide means for quickly and easily ad- ]usting the position of the brushes adapted to engage the commutator segments of the rectifier so that the alternating current waves conducted to the commutator may be cut at the proper points, this adjustment being possible while the rectifier is in opera- A further object of my invention consists in the employment of improved mechanism used in connection with starting the rectifier, these improvements residing both in the mechanical means for starting the rectifier and in the means for conducting current to the field windings of the rectifier until the rotor attains asynchronous speed.

These and other objects and advantages of my invention will be more readily understood by reference to the accompanying drawings, which show a referred embodiment of my invention, an in which- Figure 1 is a vertical ksection through my improved rectified; Fig. 2 is a plan of the rectifier shown in Fig. 1; Fig. 3 lis a horizontal section taken on the line 3-3 of Fig. l; and Fig. 4 is a horizontal section taken on the line 4-4 of Fig. 1; Fig. 5 is a diagram of they electrical connections for my rectifier.

The bracket 10 serves as a supporting means for the entire rectifier, and may be attached to a wall, panel, or the like, by the portion 11. The two arms of the bracket 10 are provided with the lupper and lower bearing members 12 and 13, respectively.

The lower bearing member 13 serves as a support for the field frame 14, which carries the pole members 15, of the usualand wellknown type, such as is described, for example, in the Letters Patent above mentioned. The lower portion 16 of the field frame 14 carries the bearing socket 17, which, in turn, supports the bearing member 18 on the lower end of the rotor shaft 19, this rotor` shaft near its upper end being supported by the bearing member 12 carried by the frame 10. The shaft 19 carries the rotor 20 consisting of laminated plates, which are suitably formed into pole faces, preferably of the same number as the field pole members 15.

The commutator 21 of the rectifier is preferably constructed of molded insulating material 22 surrounding the bushing 23, the lower end of which engages the collar 24on the shaft 19, the commutator being keyed to the shaft by means of the spline 25 which engages the shaft 19 and the bushing 23. The lower portion of the commutator 21 is provided with the conducting slip ring 26 and the upper portion is provided with a second conducting slip ring 27. The molded insulating material 22 of the commutator 21 carries a series of conducting segments 29, each of which is preferably provided with the anchoring portion 30 in order to retain the segments securely in position. In the embodiment of my linvention herein illustrated I have shown eight of the conducting segments 29. These segments are divided into two series each of which comprises four alternate segments. One series of segments is electrically connected with the slip ring 26 and the second series is similarly connected to the slip ring 27. In Fig. 1 is shown two of the segments 29 connected to the slip ring 26.' It is to be understood that the segments of the other series which are connected to the slip ring 27 are preferably of the same length as t e segments shown in Fig. 1. thereby causing the same amount of insulating material to intervene between their lower ends and the slip ring' 26 as mtervenes between the upper ends of the segments' 29 shown in Fig. 1, and the slip ring 27.

The starter plate 31, of insulating material, is keyed to the rotor shaft 19 by the spline 25, and is provided with a plurality of studs 32, which on their lower enlarged ends 33 form electrical contact. with the shp 1 brass,

` scrlbed more in detail ring 27. These studs 32 are made of copper, or other similar readily conducting material, and are preferably of the' same number as the field pole elements and the segments 29 of the commutator 21. The starter plate 31 is also provided on its upper surfacewith the conducting ring 34. As most clearly shown in Fig. 4, a spring 35, of brass or similar electrically conducting material, is fastened at one end to the starter plate 31, and is in electrical contact with the conducting ring 34. The spring member 35 partially encircles the starter plate 31, and on its free end is provided with the weighted terminal member 36, thereby forming a. governor. When the rotor 20 and the commutator 21 are rotated, on attaining a certain predetermined speed centrifugal force causes the terminal 36 to be moved outwardly so that it forms electrical contact with the inner surface of the slip ring 27. The purpose of this operation will be dei hereafter.

The bracket 37 is fastened to the insulating bushing 38 which encircles the bearing member 39 carried` by the end of the eld frame arm 40. The bracket 37 carries thereon the brush-carrier 41, which is movable in a vertical plane. At its lower end the brushcarrier 41 carries a spring-controlled brush 42 adapted to engage the conducting ring 34 and a spring-controlled brush 43 adapted to engage successively the upper ends of the studs 32 as the rotor shaft 19 revolves. When in its lower operative position, as indicated in Fig. 1, the brush-carrier 41 is maintained in position by -means of the spring-controlled stud 44, which engages the recess 45 in the brush-carrier 41. In order to move the brush-carrier to its inoperative position the stud 44 is withdrawn from the recess 45 by means of the handle 46, the cal'- rier 41 is then moved upwardly by means of its handle 47, and the stud 44 engages the lower recess 47 in the carrier 41. When the carrier 41 is in this position the brushes 42 and 43"P are out of contact with the conducting ring 34 and the studs 32, respectively.

The upper end of the rotor shaft 19 is provided with the toothed clutch member 48,

which may be engaged by the corresponding clutch member 49 carried on the lower end of the short shaft. 50, to the upper end of which is attached the handle 51. The clutch member 49 is normally maintained in its upper and disengaged position by means of the spring 52. To bring the clutch member 49 into engagement with the clutch member 48 the handler 51 is moved downwardly against the tension of the spring 52 until the shoulder 53 on the shaft 5() engages the upper surface of the bearing member 54. In order to start the rotation of the rotor, shaft'l9 and the various parts which it carries, the handle ,51 is rotated sharply, and then on releasing the downward pressure the clutch member 49 and its associated parts resume the positions shown in Fig. 1.

The field frame 14 is provided with the upper frame member 54, which carries the field arm 40, heretofore mentioned. It Will be evident from the foregoing description that the field frame andv the various parts w'hich it carries are rotatable co-axially with the-rotor shaft 19. For purposes of convenience, the amount of rotation of which the lield element is capable is preferably limited by the stop 55 of insulating material, which engages suitable detents on the main frame 10. Such detents are not shown in the drawings as they form no part of the present invention.

The upper member 54 of the field frame 14 carries the brush-holder plate 56, which is preferably in the form of a ring and which engages on its outer periphery the rollers 57 held in position by the screws 58 fastened to the frame member The. brush-holder plate 56 has at one point a regulating lug 59, which is engaged on its opposite sides by the two regulating screws 60 carried in a suitable bracket 61 fastened to the brushholder plate 56.A Each of the screws 60 is provided with a locking screw 62 to hold the regulating screws in the positions to which they have been adjusted. It will be evident that by means of the adjusting screws 60 the brush-holder plate 59 may be rotated as desired with respect to the upper plate 54 of the field frame, this brush-holder plate being always maintained in a position concentric with the axes of the rotor and field frame by means of the rollers 57.

The brush-holder plate 59 carries the post 63 having a sleeve of insulating material, which,in turn, carries the brush-holders 64, each of which supports a brush 65 held in engagement with the slip ring 26 or 27, as the case may be, by means of the spring-controlled army66 which engages the'outer end of the brush 65. The brush-holder plate 56 also carries the posts 67 and 68, each having a sleeve of insulating material and t0 each of which are fastened the brush-holders 69 each brush-holden carrying a brush 70 moved into engagement with the surface of the commutator 2l by means of the springcontrolled arm 71. The brushes carried by the posts 67 and 68 are so positioned that they simultaneously engage two of the commutator segments 29 of different series; that is, while the brushes carried by post 67 engage a segment 29 connected to slip ring 27 the brushes carried by post 68 engage a segment 29 connected' to slip ring 26, and vice-versa.

The electrical connections for the rectifier are shown in Fig. 5.' The mains 75 and 76 are connected with an alternating current generator 77, a switch Z8-being included in the mains and 76. The main 75 is connected with the lower brush 65 engaging the slip ring 26, and the conductor 79 leads from main 75 to one end of the field Winding of the pole members 15. The main 76 leads to the upper brush 65 engaging the slip ring 27. A conductor leads from brush? holder 41 to the opposite end of' the field Winding of the pole members 15, and connected to conductor 80 isconductor 81 leading to one terminal of the switch-82, to the other terminal of which is connected the conductor 83 leading to the main 76. The conductors 84 and 85 lead from the brushes 70 carried by the posts 67 and 68, respectively, and are for the purpose of conducting uni-directional current away from the rectifier, in the manner presently to be described. v

Having thus described the construction of the various parts which are used in connection with my invention, theoperation of the same may now be readily understood.

lVhen it is desired to start the rectifier the switch 78 is closed and the handle 51 is depressed until the clutch member 49 engages the clutch member 48. The handle 51 is then sharply turned in a clockwise direction, thereby causing the rotor shaft 19 and the various parts which it carries to revolve. The brush-carrier 41 has previously been lowered into the position indicated in Fig. 1. The alternating current coming to the machine through the main 76 and the upper brush 65 passes to the slip ring 27 and when the brush 43 engages one of the studs 32 this current passes up through the brush-carrier 41 and thence through conductor 80 to the field winding from which the alternating current passes through conductory 79 to the main 75, thus periodically closing the circuit when the brush 43 engages one of the studs 32. This periodical closing of the field winding circuit of course causes energization of the field pole elements, and the rotor 20 is caused to increase in its speed of rotation until centrifugal force causes the terminal element 36 to be moved outwardly until it engages the inner surface of the slip ring 27. The parts are so adjusted that this latter operation takes place when synchronous speed is attained. When the terminal 36 engages the slip ring 27, thev current passes directly from the slip ring 27 through the terminal 36 and the spring member 35 to the conducting ring 34 and thence through the brush 42, the brush-carrier 41 and the conductor 8O to the field winding. When this condition takes place the field winding' is continuously in circuit with the source of alternating current and the rotor 20 is maintalned at synchronous speed. The

switch 82 is now closed and the field winding is thus permanently and directly connected in shunt with the source of alternatcurrent.

ing current. The brush-holder 41 may then be raised, thereby causing the brushes 42 and 43 to be disengaged 'from the conducting ring 34 and the upper ends of the studs 32. The alternating current which is introduced through the brushes 65 into the slip rings 26 and 27 passes into the'segments 29 con*` nected with these slip rings, and by reason of the synchronous rotation of the commutator 21, the current delivered to the brushes 70 becomes uni-directional pulsating current, the current delivered to the brushes 70 carried by the post 67 being of one polarity, and that delivered to the brushes 70 carried by the post 68 being of the opposite polarity. This unidirectional current is conducted away from the rectifier through the conductors 84 and 85 connected with the brushes 70.

As explained in detail in the Harris patents above mentioned, the maintenance of perfect synchronism is attained by mounting the field element so that it may freely oscillate to adjust itself to any Variations in the wave phasesv of the source of alternating Oscillation of the field causes the brushes 70 to move correspondingly with reference to the commutator segments 29. It

rwith relation to the field elements, so that the waves of the alternating current will be cut at the proper points, perfect synchronism meanwhile being maintained in the manner just explained. In order to make the adjustment of the brushes 70 the adjusting screws 60 may be moved as required, thereby moving the brushes 70 to exactly the proper positions with respect to the segments' 29 when the rotor 20 is in a given position with relation to the field elements 15. This adjustment may readily be effected while the rectifier is operating.

It will be apparent to those skilled in the art that many detailed changes could be made in the various parts Which I have described Without departing from the spirit or scope of my invention.

What I claim is:

1. In a rectifier, the combination of afield frame, a rotor, a commutator mounted for rotation With said rotor, a pair of slip rings, one of said slip rings having a plurality of conducting elements electrically connected thereto, a conducting ring insulated from said slip ring, a conducting brush-carrier having a pair of brushes, one of which is adapted to engage successively said conducting elements and the other of which is adapted to engage said conducting ring, and a governor adapted to connect said slip ring with said conducting ring when a predetermined speed of rotation of said commutator is attained, Whereby'below said predetermined speed said brusl1carrier is intermittently electrically connected with Said slip ring, and at or above said Dredetermined speed said brush-carrier is continuously electrically connected with said slip ring.

2. In a rectifier, the combination of a field frame, la rotor, a commutator mounted for rotation with said-rotor, a pair of slip rings, one of said slip rings having 'a plurality of conducting elements electrically connected thereto, a conducting ring insulated from said slip ring, a conducting brush-carrier having a pair of brushes, one of which is adapted to engage successively said conducting elements and the other of which is adapted to engage said conducting ring, a governor adapted to Connect said slip ring with said conducting ring when a predetermined speed of rotation of said commutator is attained, whereby below said predetermined speed said brush-carrier is intermittently electrically connected with said slip ring, and at or above said predetermined speed said brush-carrier is continuously electrically connected with said slip ring, a clutch member carried by said rotor, a second clutch member adapted to engage said first clutch member for starting the vrotation of said rotor, and spring means normally holding said second clutch member out of engagement with said first clutch member.

3. In a rectifier, the combination of a field frame, a rotor shaft having a rotor mounted thereon, a commutator carried by said shaft, a clutch member on said shaft, a second clutch member. adapted to engage said first clutch member, whereby the rotation of said rotor may be started by rotating said second clutch member, and spring means normally holding said second clutch member out of engagement with said rst clutch member.

In witness whereof, I hereunto subscribe my name this 2nd day of February, A. D.

JOHN M. FITZGERALD. Witnesses:

HENRY M. I-IUXLEY, L. E. HANNEN. 

